Scimat Limited

Raychem Limited

Scimated Limited

John A Cook

Robert H McLoughlin

George B Park

Raymond William Singleton

Kenneth Gargan

Giovanni Gentilcore

David J Barker

Iain S Smith

Stephen E Myers

Geroge B Park

William J Whitcher

Mike G Dorling

Non-woven fabrics are disclosed comprising substantially unbonded fibers and vinyl monomers which are capable of reacting with an acid or a base to form a salt directly or indirectly by a reaction involving exposure to ultraviolet radiation while impregnated with a solution of the vinyl monomer copolymerized to the surface of the fibers. Laminates of these non-woven fabrics as well as electrochemical devices employing them as a separator, and methods of treating such non-woven fabrics are also disclosed.

Non-woven fabric treatment

Polymeric sheet

A polymeric sheet, which is particularly suited for use as a separator in an electrochemical device, is formed by graft copolymerizing acrylic acid, or another vinyl monomer capable of reacting with an acid or a base to form a salt directly or indirectly with fibers of a non-woven sheet, whose outer surface is provided by a polyolefin, especially polypropylene. The polyolefin is crosslinked as a result of the polymerization reaction. The polymerization reaction is preferably initiated by exposure of the sheet to ultraviolet radiation, after impregnation with an appropriate solution of the vinyl monomer.

Polymeric sheet and electrochemical device using the same

Fluid filled and collapsing polymeric filter tube having a supporting

Polymer membrane

Process for making a composite membrane

A microporous polymeric film of high porosity comprises a halopolymer in which the repeating units are --(C.sub.n H.sub.2n)-- and --(C.sub.m X.sub.2m)-- in which each X independently represents fluorine or chlorine and the values of n and m are greater than one and less than six. The film is the result of firstly melt processing a mixture of the halopolymer, more than 150 parts by weight of an extractable salt and not more than 80 parts by weight of an extractable polymer per 100 parts by weight of the halopolymer, the extractable polymer not being completely and homogeneously mixed with the halopolymer and being less viscous than the halopolymer when both are molten so that the surfaces of the film resulting from melt processing are rich in the extractible polymer, and secondly extracting at least some of the extractable salt to render the film porous and extracting at least some of said polymer to impart surface porosity to the film. The film has a porosity of more than 50% by volume and more usually 60-70%. The film may be used as the separator of an electrochemical cell e.g. a battery having a lithium anode and a thionyl chloride electrolyte.

Microporous films

Melt-extruded polymeric electrolyte material for electrochemical power cells may be coextruded with other components of the cell, notably a lithium metal anode.

Method for making a polymeric electrolyte

A method of making a plugged microporous film from a film which comprises a structural component having pores extending therethrough, and a plugging material within the pores, the method comprising:

Plugged microporous film

Sensitive electrode material, e.g. lithium electrode material, protected by a flexible layer of material which is swellable by liquid with which it will come into contact in use, and can thus, for example, act as an electrode separator when assembled in an electrical cell containing such a liquid. The protected electrode material can be processed, e.g. rolled into thin sheets, and can conveniently be fed to automatic cell assembly apparatus.

Electrode article

Sensitive material, e.g. lithium electrode material, is provided with a protective layer of fluid-impermeable material, which is subsequantly rendered permeable by altering its physical structure, e.g. by perforation, without altering its composition. The permeable material can act, for example, as an electrode separator when the resulting article is assembled into an electrolytic cell, and the protected material can be processed, e.g. rolled into thin sheets, and conveniently fed to automatic assembly apparatus.

Protection of sensitive material

Materials for electrical devices

An article which is rendered waterproof by a microporous membrane of a hydrophobic material, the pores of the membrane in a layer-like region on or towards a surface thereof being plugged with a hydrophilic material, leaving hydrophobic material exposed on the said surface between the pores.

Waterproof article and method for making a waterproof article

A protected electrode article comprising sensitive electrode material having a layer of protective material bonded to at least part of its surface by means of an adhesive which can be made to swell by treatment with liquid, so as to increase the permeability of the adhesive to electrolyte which is encountered by the protected electrode material when incorporated in an electrochemical device.

Protected electrode article

Continuous metal electrodes are protected by non-porous fluid-impermeable material which is convertible to a fluid-permeable (porous) state, enabling the protective material to act as an electrode separator after the conversion. Conversion by contact with the non-aqueous fluid in a lithium cell is preferred, using strips of lithium protected with a blend of polyethylene and polyethylene oxide, the latter being extractable by the cell liquids.

Growing community of inventors

Faringdon, United Kingdom

John A Cook